Rapid assessment of seed promoters in leaves by using LEC2 transcriptional factor

LEC2 as a transcriptional factor attaches to seed-specific promoters and induces the expression of downstream genes. Analysis of permanent gene transfer in plants is time-consuming and has long process. Using this transcription factor along with the agroinfiltration method can reduce significantly the time of seed specific promoter evaluation. In this research, seed specificity of FAD2-1 promoter, isolated from safflower plants, was studied by GUS expression analysis in tobacco leaves. Fad2-1 promoter sequence analysis indicated that this promoter is containing essential elements for seed-specific function. For analyzing FAD2-1 promoter function, we constructed two gene cassettes: pFAD2-GUS (GUS gene under the control of FAD2-1 promoter) and pBI-LEC2 (LEC2 gene under the control of CaMV35S promoter). These cassettes were cloned in pBI121 vector and transferred to Agrobacteriun tumefacience EHA105, separately. For seed-specific function analysis of FAD2-1 promoter in tobacco leaves, the overnight culture of Agrobacteriums were adjusted to OD600=0.6, mixed equally and then used to infiltrate into tobacco leaves. GUS assay analysis of infiltrated leaves indicated the specific expression of the reporter gene (GUS). Therefore, FAD2-1 promoter is suggested as a seed specific promoter. Our results suggest that LEC2 along with agroinfiltration method can use as a rapid and confident tool for verifying seed specific expression of any seed-specific promoters.